The present invention concerns a press for pressing wood particles and a suitable bonding agent into particleboard.
A press for executing a surface pressing procedure is known from Offenlegungsschrift No. 25 45 366, in which several frames aligned one after the other in spaced relationship constitute the support structure for a continuous press. Heated upper and lower platens connected to the support structure are arranged so that the distance between them is continuously decreased to a press opening corresponding to the thickness of the particleboard. The mass of wood particles on a suitable bonding agent is pressed between the platens until a constant thickness has been achieved, and hydraulically activated pistons are used to move the platens. For the production of particleboard, transport devices are also required for introducing mats of binder coated wood particles into the continuous press and for removing pressed particleboards therefrom. Such transports may encircle the upper and lower platens and be in the form of roller-flights, as shown for example in German Auslegeschrift No. 22 42 399.
In presses of this type, roller-flights leave impressions on the particleboard to be pressed, and in addition, maintaining the dimension of the press opening constant requires considerable expense since the constancy is maintained by means of hydraulic control. Use of the roller-flights according to German Auslegeschrift No. 24 45 624 does not prevent the impressions in the surface of the particleboard to be pressed, and the expense of the hydraulic control for keeping the press opening constant is high.
Likewise, a simple visible control of the required distance between the platens for manufacturing particleboard with practically constant thickness resulting from the hydraulic control of both platens cannot be obtained by means of discontinuously operating press platens, known from German Auslegeschrift No. 17 03 297 and each provided with self-compensating cylinder and piston devices. The press consists of one movable and one fixed press brace, between which one or several pairs of platens are arranged. Press posts are provided and each one consists of two columns and a connecting piece. Cylinder and piston mechanisms are provided at the long sides of the press braces, the press being characterized by compensation pistons provided between the fixed and the movable press brace and between the corresponding press platens.